Photothermal Conversion Materials Research Articles

Coordination assembly and NIR photothermal conversion of Metal-organic framework based on 5-(2-cyanophenoxy) isophthalic acid

The development of new photothermal conversion materials in the field of metal-organic frameworks (MOFs) shows broad prospects, but their design synthesis and proper mechanism analysis are still full of huge challenge. Here, four novel MOFs were constructed with 5-(2-cyanophenoxy) isophthalic acid, {Ni(2-CB-IPA)(bpp)(H2O)}n (1), {Ni2(2-CB-IPA)2(bpa)2(H2O)2}n (2), {Co(2-CB-IPA)(bpp)}n (3), {Mn2(2-CB-IPA)2 (bpp)(H2O)2}n (4). (Where 2-CB-IPA = 5-(2-cyanophenoxy) isophthalic acid, bpa = 1,2-bis(4-pyridine)-ethane; and bpp = 1,3-bis(4-pyridyl)propane). The absorption peak at 730 nm in the near-infrared region indicates that different charge transfer interactions affect the photothermal conversion ability. Under laser irradiation (730 nm, 0.45 W cm−2), such compounds exhibit different and distinct warming processes (1 from 20.8 to 91.8 °C; 2 from 20.1 °C to 86.2 °C; 3 from 20.6 to 77.1 °C) except for compound 4. The excellent crystallinity of these materials after irradiation demonstrates excellent thermal stability and cycling durability. Subsequently, further research on the structure-activity relationship revealed that strong π - π interactions are also the reason for the excellent performance of NIR photothermal conversion of 1 under the premise of high NIR absorption. This work provides a visual platform for the photothermal phenomena of crystalline materials.

Three-dimensional NiO/Ni self-floating porous composite materials for efficient solar interfacial evaporation

The scarcity of freshwater resources and energy crisis are major challenges to the progress of human society. Recently, solar-driven interfacial water evaporation utilizes photothermal conversion materials to convert solar energy into thermal energy, which possesses great application potential in seawater desalination and sewage treatment. Here, we fabricated porous nickel sponge (NSP) composite photothermal material (NiO-NSP) containing abundant NiO nanoneedles array. This in situ-grown NiO with enhanced bonding between photothermal material and substrate can be used as a solar absorber directly without consuming additional photothermal material compared to conventional coating and cladding on the carrier surface. Due to the multi-scattering induced light trapping effect of the semiconductor NiO nanoneedles array on the surface of nickel fibers, resulting in light absorption up to 96.5 %. NiO-NSP evaporators have an abundance of interconnected porous channels for water supply, which results in strong capillary action to pump water to the evaporation interface efficiently. Moreover, the highly dispersed nanoneedles array expand the evaporation surface area. Consequently, the NiO-NSP evaporator delivers an excellent evaporation rate of 1.78 kg m−2 h−1 and a photothermal conversion efficiency of 84.7 % at one sun radiation. In addition, the micron-sized porous mesh structure of NiO-NSP dissolve salt crystals and diffuse them downward into the bulk brine, exhibiting excellent salt resistance and remarkable seawater desalination stability. Moreover, NiO-NSP solar evaporators has been demonstrated to possess excellent ability to purify dye and heavy metal ion wastewater. Therefore, the NiO-NSP high-performance evaporator produced by straightforward process proved to be suitable for solar seawater desalination and wastewater purification.

Flexible Janus Black Silicon Photothermal Conversion Membranes for Highly Efficient Solar-Driven Interfacial Water Purification.

Photothermal conversion materials are critical in the development of solar-driven interfacial evaporation techniques; however, achieving a high energy conversion efficiency remains challenging owing to the high cost and instability of light-absorbing materials, in addition to the difficulties of simultaneously improving light absorption while suppressing heat loss. A black silicon (Si) powder with a porous structure was prepared by chemical etching of a low-cost commercial micron-sized Al-Si alloy, and a flexible Janus black Si photothermal conversion membrane was constructed. The partially broken spherical particles and porous structure obtained after etching enhanced the refraction of light from the Si powder, imparting the prepared membrane with an average light absorption rate of 95.95% over the solar spectrum. Evaporation from the membrane increased the intermediate water content and reduced the equivalent evaporation enthalpy. The thermal conduction loss was inhibited through a one-dimensional water transport structure, and the membrane achieved a water evaporation rate of 2.17 kg m-2 h-1 and a photothermal efficiency of 94.95% under 1 sun illumination. Benefiting from the broadband absorption and high photothermal efficiency of black Si powder, surface modification of hydrophobic polydimethylsiloxane, and directional salt-out structure design, the evaporation rate of the Janus black Si membrane-based system in a 10% NaCl solution was maintained >2.10 kg m-2 h-1 after 7 days of continuous evaporation cycles. The removal rate of metal ions from simulated seawater and from practical wastewater containing complex heavy metals reached >99.9%, indicating the promising potential of black Si membrane for application in solar-driven interfacial water purification.

Comparative experimental study on photothermal conversion and shape memory properties of MF-based flexible composite phase change materials loaded with carbon nanotubes and polydopamine

Efficient use of solar energy can effectively alleviate the problem of energy shortages. Currently, extensive researches have been carried out on photothermal conversion materials. However, factors such as photothermal conversion and thermal conductivity limit the practical implementation of photothermal materials. In this research, a novel flexible composite phase change material (CPCM) with melamine foam (MF) as the supporting skeleton, carbon nanotube (MWCNT)/polydopamine (PDA) as the light-absorbing coating and polyethylene glycol (PEG) as the energy storage material was successfully prepared. The results show that the MF-based CPCMs have good shape stability with a leakage of only 0.9 %, and high phase change enthalpies, the melting enthalpy was above 172.0 J/g. In addition, the thermal conductivity was improved due to the introduction of light-absorbing coatings into the CPCMs. Compared with MF/PEG, MWCNT/MF/PEG, and PDA/MF/PEG, MWCNT/PDA/MF/PEG were improved by 35.21 %, 8.6 % and 29.46 %, respectively. Finally, the average charging efficiency of MWCNT/PDA/MF/PEG is 96.26 %, which is 62.33 % and 20.1 % higher than that of MWCNT/MF/PEG and PDA/MF/PEG respectively, indicating that MWCNT and PDA nanofillers played a synergistic role in enhancing the performance of CPCMs. This study provides new and innovative ways for the design of photothermal materials.

All-in-one strategy to develop a near-infrared triggered multifunctional bioactive magnesium phosphate bone cement for bone repair

Bone cement is widely used in clinical with optimistic filling and mechanical properties. However, the setting time of bone cement is difficult to accurately control, and the existing bone cements exhibit limited therapeutic functionalities. In response to these challenges, we designed and synthesized Nd-doped whitlockite (Nd-WH), endowing bone cement with photothermal-responsive and fluorescence imaging capabilities. The doping amount and photothermal properties of Nd-doped whitlockite were studied, and the composite bone cement was prepared. The results showed that the setting time of bone cement could be regulated by near infrared irradiation, and the multiple functions of promoting osteogenic differentiation, antibacterial and anti-tumor could be realized by adjusting the power and irradiation time of near infrared. By incorporating Nd-doped whitlockite and bone cement, we developed an all-in-one strategy to achieve setting time control, enhanced osteogenic ability, tumor cell clearance, bacterial clearance, and bone tissue regeneration. The optimized physical and mechanical properties of composite bone cement ensure adaptability and plasticity. In vitro and in vivo experiments validated the effectiveness of this bone cement platform for bone repair, tumor cell clearance and bacterial clearance. The universal methods to regulate the setting time and function of bone cement by photothermal effect has potential in orthopedic surgery and is expected to be a breakthrough in the field of bone defect repair. Further research and clinical validation are needed to ensure its safety, efficacy and sustainability. Statement of significanceBone cement is a valuable clinical material. However, the setting time of bone cement is difficult to control, and the therapeutic function of existing bone cement is limited. Various studies have shown that the bone repair capacity of bone cements can be enhanced by synergistic stimulatory effects in vivo and ex vivo. Unfortunately, most of the existing photothermal conversion materials are non-degradable and poorly biocompatible. This study provides a bone-like photothermal conversion material with photothermal response and fluorescence imaging properties, and constructed a platform for integrated regulation of the setting time of bone cement and diversification of its functions. Therefore, it helps to design multi-functional bone repair materials that are more convenient and effective in clinical operation.

Ginseng‐Bioinspired 3D Photothermal Evaporator for Efficient Seawater Desalination Using Conjugated Microporous Polymer

AbstractPhotothermal conversion technology presents a promising approach for harnessing solar energy to facilitate seawater desalination. However, salts will accumulate on the surface of the photothermal conversion structure during seawater desalination, which hinders solar energy absorption. Meanwhile, the photothermal conversion structure directly immersing in a large water body results in a large heat dissipation loss. Both factors impair solar energy conversion and water steam generation. To address the issues, inspired by a ginseng plant (with a trunk‐to‐branch water supply system), a 3D cotton‐based photothermal evaporator with tunable water supply is facilely designed herein via simple cloak‐weaving of a porphyrin‐based conjugated microporous polymer (PPCMP) as the photothermal conversion material. The as‐designed 3D cloak‐like photothermal evaporator achieves an equilibrium between the water supply flux and evaporation rate via optimizing PPCMP weaving and the water path. As a result, a high evaporation rate of 2.81 kg m−2 h−1 and photothermal conversion efficiency of 155% are obtained under 1 sun illumination. The findings underline the importance of 3D porous organic polymer‐based fabrics as effective media for harnessing solar energy and highlight their potential for seawater desalination.

Photothermal performance of vitreous products from high-temperature melting of hazardous waste

High-temperature molten vitreous (HTMV), as the primary means of hazardous waste disposal, was produced in large quantities. Exploring its potential in photothermal applications could extend its high-value. Herein, the HTMV was used to explore the photothermal performance potential. It indicates that the HTMV possesses significant photothermal conversion capability, capable of increasing the tested water temperature by 6.65 °C. The HTMV mass and water volume are critical factors affecting the water temperature outcomes. The HTMV exhibits distinct conversion capabilities when applied at different application scenarios on the test object. Application on the bottom primarily focuses on photothermal conversion with high heat production efficiency, while side application additionally demonstrates excellent thermal insulation properties. Based on heat balance and backpropagation neural network predictions, optimal scheme of HTMV on both inside and outside bottom application scenarios of the heated object can achieve a maximum heat input of 660.6 kJ m−2 and 570.1 kJ m−2, respectively, and reduce carbon emissions by 0.062 kg CO2 m−2 and 0.054 kg CO2 m−2. This study not only provides a foundation for the further application of HTMV but also opens a new direction for the development of photothermal conversion materials, which is of great significance in advancing sustainable energy technology.

MXene/Ag3PO4 modified PVDF composite membranes for efficient interfacial evaporation and photodegradation

Solar-powered interface evaporation is considered a promising technology to obtain freshwater from non-potable water by using sustainable solar energy. However, research on combining the photocatalytic effect with solar interfacial evaporation technology to go for photothermal conversion materials with full solar spectrum utilization for photothermal and photodegradation capabilities is still scarce. Due to the unique optical properties of MXene, a novel MXene/Ag3PO4-based membrane with synergistic photothermal and photocatalytic effects was developed from the perspective of practical applications such as water purification, photodegradation of organic dyes and antibacterial properties. In this paper, polyvinylidene fluoride (PVDF) and carbon black (CB) were used as the substrate, calcium carbonate (CaCO3) and hydrochloric acid (HCl) were selected as the pore-forming agent for hydrophilic modification, and MXene/Ag3PO4 serves as the photocatalyst. The prepared composite polyvinylidene fluoride membrane (PCC-MXene/Ag3PO4) with Schottky junction, possesses a rich pore structure, abundant water molecule transport channels, high light absorption ability, and low thermal conductivity, which lead to a good performance in solar interface evaporation, photodegradation and antibacterial. The superhydrophobicity and floatability of the nanosponges in water enable them to continuously pump water, which greatly promotes the dissolution of salt accumulation. With the help of porous nanosponges, PCC-MXene/Ag3PO4 exhibits excellent evaporation stability and salt resistance under 1 kW m−2 solar irradiation, as well as photodegradation of organic dyes. In addition, the PCC-MXene/Ag3PO4 membrane has the properties of self-buoyancy, electrical conductivity, and superior flexibility. Therefore, considering the simple preparation method and fine performances, the PCC-MXene/Ag3PO4 mixed membrane has great application potential in the study of interface evaporation, photodegradation of organic dyes, and antibacterial properties.

Carboxymethylcellulose sodium-derived carbon aerogels for solar-driven water purification

Recycling polluted water via different techniques has become one of the most feasible ways to solve the freshwater crisis. We describe a novel method to prepare reusable and efficient photothermal energy conversion materials for water purification. Using crosslinked xerogels as precursor, the porous and interconnected carboxymethylcellulose sodium-derived carbon aerogels (abbreviated as CCAs) with good hydrophilic performance and strong light absorption capability are firstly fabricated through pyrolysis. Photothermal measurement results show that CCA15 exhibit excellent solar steam generation rate of 2.31 kg m−2 h−1 with high light-to-vapor conversion efficiency of 95.9% under 1 sun illumination. In addition, the feasible application of CCA15 for efficient water purification under 1 sun irradiation using a homemade water treatment device has been demonstrated successfully. The as-prepared CCAs shown in here can be a continuable solution to mitigate the global freshwater crisis.

Solid waste reutilization of FCC petroleum coke for solar evaporation as a photothermal conversion material

Petroleum coke is a common industrial waste and is generally considered to be an amorphous carbonaceous or highly aromatized polymer carbide. In this study, petroleum coke was used as the main raw material and loaded on a nonwoven fabric to construct an interfacial solar evaporator with a micro-nano structure. The light absorption, evaporation rate and photothermal efficiency of CB@EM with different loading concentrations were investigated with different light intensities, coming in to evaluate the photothermal conversion performance of CB@EM. The results showed that the petroleum coke was resistant to acid and alkali. The simply prepared CB@EM has excellent photothermal conversion performance, and the evaporation rates of 50-CB@EM were 1.37, 2.34, and 5.61 kg m−2 h−1 at 0.5 sun, 1 sun, and 1.5 sun, respectively; meanwhile, the average evaporation rate of 50-CB@EM after 60 h of continuous evaporation at 1 sun, which realized efficient and continuous water evaporation was 2.39 kg m−2 h−1, the evaporation efficiency was 93.29 %, and the salt would preferentially accumulate from both ends of 50-CB@EM. In addition, CB@EM has flame retardancy, which can reduce the risk of fire during transportation. This study provides a method to treat petroleum coke industrial waste residue using clean energy and apply it in solar photo-thermal water evaporation, which has great potential for industrial application.

Photo-thermal catalysis for sustainable energy production and environmental treatment

Photo-thermal-catalysts (PTC) exceptional features and ability to concurrently solve sustainable energy requirements and environmental problems have drawn scientific interest. The photo-thermal effect is the process by which photo-thermal conversion materials transform radiant energy from light into thermal energy. The photo-thermal therapy of energy and environmental treatment faces the urgent task of developing effective photo-thermal agents to address complicated problem demands. In this study, we take a look at the fundamental principles and underlying process of photo-thermal material catalysis. In addition, this review provides a concise summary of the most up-to-date findings concerning photo-thermal catalysis materials, which have been aggressively researched for a wide-spread sustainable energy and environment treatment uses. In order to motivate the creation of a high-efficiency photo-thermal catalytic pathway, the criteria and techniques for designing photo-thermal catalysts are presented. This will make it possible for a better absorption of the whole spectrum of solar energy as well as a greater conversion of solar energy to heat. Theoretical direction is offered for the continued development of this technology, and the promise of the practical use of photo-thermal catalysis for different solar-driven interfacial photo-thermal conversion technologies is anticipated. This paper offers a unique perspective on photo-thermal catalysis focussing on the synergistic effects and suggesting a potential route for future applications.

Study on the photothermal conversion enhancement performance and application of the metal-polyphenol phase-change microcapsules modified by molybdenum disulfide

Aiming to improving photothermal conversion and heat storage efficiency, layered molybdenum disulfide (MoS2) was prepared with hydrothermal method, which was used as the thermally conductive and photothermal conversion material to modify metal-polyphenol (MPN) /paraffin (PA) microcapsules. The fabricated phase-change microcapsules (MoS2/MPN@PA-MEPCM) exhibits excellent thermal conductivity, photothermal conversion and heat storage performance. The effect of the additive amount of MoS2 on the leakage performance, microstructure, thermal conductivity, heat storage capacity, thermal stability and photothermal conversion performance of MoS2/MPN@PA-MEPCM was investigated. Furthermore, the enhancement mechanisms of the thermal conductivity and photothermal conversion were analyzed. The results show that when the additive amount of MoS2 is 10 wt%, the phase-change enthalpy of MoS2/MPN@PA-MEPCM reaches 127.1 J/g with an encapsulation ratio of 53.74 %. Compared to MPN@PA-MEPCM, the thermal conductivity of MoS2/MPN@PA-MEPCM increases by 88.45 % and the photothermal conversion and heat storage efficiency reaches 90.78 %. When the solar radiation intensity is 800 W/m2 and 1000 W/m2, the thermal efficiency of PFPSC is 57.17 % and 59.45 % respectively, which is higher than that of FPSC. The operation time of PFPSC is extended by 2435 s and 2750 s, respectively, improving the operational stability of flat plate solar water heaters. The developed microcapsules in this study demonstrate significant potential for highly efficient solar energy utilization and thermal energy storage in the fields of seawater desalination, solar water heating system and building heating.

Preparation and characteristic of palmitic acid/flower-shaped CuS composite phase change material for effective heat storage and photothermal conversion

Designing and synthesizing the excellent heat storage and photothermal integrated composite phase change materials (PCMs) is an effective strategy for solar energy utilization. This work focuses on two kinds of CuS (cuboidal and 3D flower-shaped) with different morphology were designed as substrates and photothermal materials, and PA/F–CuS and PA/C–CuS composite PCMs have been prepared by melt-blending and vacuum impregnation method. Through SEM and pore structure characterization as well as leakage testing, it is proved that 3D layered flower-shaped CuS not only exposes the large specific surface area and rich adsorption sites, but also 2D thin layers can perform multiple reflections to improve the utilization rate of solar energy. The flower-shaped CuS is more suitable for the supporting material. Noteworthy, the latent heat of PA/F–CuS can reach 226.3 J/g, and the thermal conductivity is 0.3447 W/(m·K). Furthermore, compared with pure PA, the photothermal property of PA/F–CuS increased by 49.22–84.59%, and the photothermal conversion efficiency can reach 70.3%. This work provides an innovative idea for the design and manufacture of composite PCMs related to medium and low temperature solar energy storage, and has broad application potential in the field of thermal energy storage such as solar energy utilization and building insulation materials.

Enhanced near-infrared absorption of Cs0.32WO3 nanoparticles for efficient interfacial solar steam generation

Solar steam generation has gained significant attention as a promising method for clean and sustainable water purification and desalination. The spectral absorption performance of the photothermal conversion material directly affects its thermal conversion efficiency. This research investigates the enhanced near-infrared absorption of Cs0.32WO3 nanoparticles for efficient interfacial solar steam generation. In this study, Cs0.32WO3 nanoparticles were synthesized using a simple co-precipitation and heat treatment method. The synthetic nanoparticles were then incorporated into a porous membrane to create a photothermal conversion material for solar steam generation and their near-infrared absorption properties were characterized. The experimental results demonstrated that the Cs0.32WO3 nanoparticles effectively converted solar energy into heat, resulting in efficient interfacial steam generation. The membrane showed a high evaporation rate of of ∼ 3.15 kg·m−2·h−1 under one sun illumination. The findings of this study provide valuable insights into the design and development of efficient solar steam generation systems using near-infrared absorption nanomaterials.

Radical‐Induced Photochromic Silver(I) Metal‐Organic Frameworks: Alternative Topology, Dynamic Photoluminescence and Efficient Photothermal Conversion Modulated by Anionic Guests

Photogenerated radicals are an indispensable member of the state‐of‐the‐art photochromic material family, as they can effectively modulate the photoluminescence and photothermal conversion performance of radical‐induced photochromic complexes. Herein, two novel radical‐induced photochromic metal‒organic frameworks (MOFs), [Ag(TEPE)](AC)⋅7/4H2O⋅5/4EtOH (1) and [Ag(TEPE)](NC)⋅3H2O⋅EtOH (2), are reported. Distinctly different topological networks can be obtained by judiciously introducing alternative π–conjugated anionic guests, including a new topological structure (named as sfm) first reported in this work, describing as 4,4,4,4‐c net. EPR data and UV‐Vis spectra prove the radical‐induced photochromic mechanism. Dynamic photochromism exhibits tunability in a wide CIE color space, with a linear segment from yellow to red for 1, while a curved coordinate line for 2, resulting in colorful emission from blue to orange. Moreover, photogenerated TEPE* radicals effectively activate the near‐infrared (NIR) photothermal conversion effect of MOFs. Under 1 W cm‐2 808 nm laser irradiation, the surface temperatures of photoproducts 1* and 2* can reach ~160 ℃ and ~120 ℃, respectively, with competitive NIR photothermal conversion efficiencies η = 51.8% (1*) and 36.2% (2*). This work develops a feasible electrostatic compensation strategy to accurately introduce photoactive anionic guests into MOFs to construct multifunctional radical‐induced photothermal conversion materials with tunable photoluminescence behavior.

Radical-Induced Photochromic Silver(I) Metal-Organic Frameworks: Alternative Topology, Dynamic Photoluminescence and Efficient Photothermal Conversion Modulated by Anionic Guests.

Photogenerated radicals are an indispensable member of the state-of-the-art photochromic material family, as they can effectively modulate the photoluminescence and photothermal conversion performance of radical-induced photochromic complexes. Herein, two novel radical-induced photochromic metal‒organic frameworks (MOFs), [Ag(TEPE)](AC)⋅7/4H2O⋅5/4EtOH (1) and [Ag(TEPE)](NC)⋅3H2O⋅EtOH (2), are reported. Distinctly different topological networks can be obtained by judiciously introducing alternative π-conjugated anionic guests, including a new topological structure (named as sfm) first reported in this work, describing as 4,4,4,4-c net. EPR data and UV-Vis spectra prove the radical-induced photochromic mechanism. Dynamic photochromism exhibits tunability in a wide CIE color space, with a linear segment from yellow to red for 1, while a curved coordinate line for 2, resulting in colorful emission from blue to orange. Moreover, photogenerated TEPE* radicals effectively activate the near-infrared (NIR) photothermal conversion effect of MOFs. Under 1 W cm-2 808 nm laser irradiation, the surface temperatures of photoproducts 1* and 2* can reach ~160 ℃ and ~120 ℃, respectively, with competitive NIR photothermal conversion efficiencies η = 51.8% (1*) and 36.2% (2*). This work develops a feasible electrostatic compensation strategy to accurately introduce photoactive anionic guests into MOFs to construct multifunctional radical-induced photothermal conversion materials with tunable photoluminescence behavior.

Photothermal Conversion Porous Organic Polymers: Design, Synthesis, and Applications.

Solar energy is a primary form of renewable energy, and photothermal conversion is a direct conversion process with tunable conversion efficiency. Among various kinds of photothermal conversion materials, porous organic polymers (POP) are widely investigated owing to their controllable molecular design, tailored porous structures, good absorption of solar light, and low thermal conductivity. A variety of POP, such as conjugated microporous polymers (CMP), covalent organic frameworks (COF), hyper-crosslinked porous polymers (HCP), polymers of intrinsic microporosity (PIM), porous ionic polymers (PIP), are developed and applied in photothermal conversion applications of seawater desalination, latent energy storage, and biomedical fields. In this review, a comprehensive overview of the recent advances in POP for photothermal conversion is provided. The micro molecular structure characteristics and macro morphology of POP are designed for applications such as seawater desalination, latent heat energy storage, phototherapy and photodynamic therapy, and drug delivery. Besides, a probe into the underlying mechanism of structural design for constructing POP with excellent photothermal conversion performance is methodicalized. Finally, the remaining challenges and prospective opportunities for the future development of POP for solar energy-driven photothermal conversion applications are elucidated.

A silver-loaded graphene oxide-functionalized Bi-Photothermal composite nanofiber membrane for solar-driven desalination

We have identified a synergistic effect between graphene oxide (GO) and silver (Ag) that significantly enhances the light absorption capacity of silver-loaded graphene oxide (GO-Ag) composite materials. Here we have developed a bi-photothermal electrospun nanofiber membrane (EFM), combining the GO-Ag and polyacrylonitrile (PAN), to improve solar-driven desalination. The characterization results demonstrate that GO-Ag uniformly dispersed within the fiber membrane as a photothermal conversion material enables the GO-Ag/PAN EFM to achieve a remarkable optical absorption of 97 %. And under 1 sun irradiation, the membranes rapidly reach a maximum temperature of 56.3 °C, showcasing exceptional photothermal conversion ability during evaporation. Additionally, the super-hydrophilic porous materials GO-Ag/PAN EFMs exhibit an impressive water evaporation rate of 1.61 kg m-2h−1, accompanied by a photothermal conversion efficiency of 93.3 % under 1 sun. Moreover, the GO-Ag/PAN EFMs demonstrate a remarkable desalination of 99.9 % and salt resistance performance for seawater.

Solar interfacial evaporation for efficient treatment of sewage containing volatile organic compounds and toxic heavy metal ions: A sequential process of adsorption, coagulation, and evaporation

Solar interfacial evaporation (SIE) is an eco-friendly and sustainable technology for addressing water pollution and freshwater scarcity. However, treating wastewater containing volatile organic compounds and heavy metal ions with a single SIE method is inefficient. The combination of adsorption, coagulation, and evaporation process provides an alternative solution for treating this type of wastewater. In this study, activated carbon powder (C) is introduced as an adsorbent and an integral part of photothermal conversion material, which is coagulated with polyvinyl alcohol (PVA) and polyethylene glycol (PEG) through a mold press process to fabricate PVA/C/PEG composite hydrogels. The volatile organic compounds and heavy metal ions in the wastewater are adsorbed by the activated carbon powder and the wastewater is then further purified into freshwater through SIE. This stepwise “adsorption first, then coagulation and evaporation” method can not only rapidly remove pollutants from the raw water, but also provides a much higher removal efficiency than the adsorption-evaporation synergetic process. This work demonstrates a successful attempt to utilize the SIE method for treating wastewater containing volatile organic compounds and heavy metal ions.

Spongy polyelectolyte hydrogel for efficient Solar-Driven interfacial evaporation with high salt resistance and compression resistance

The hydrogel-based evaporator for interface evaporation provides a method for sustainable freshwater production. However, salt accumulation on the surface of the steam generator affects light absorption and reduces steam generation efficiency. Achieving a high-performance, salt-resistant steam generator remains challenging. Here, sponge-like polyelectrolyte composite hydrogel-based solar steam generator (MPS) is reported. The steam generator is designed with an interpenetrating network topology and is made by in-situ polymerizing sodium polyacrylate (P(SA)) in a sponge-like polyvinyl alcohol (PVA) hydrogel framework, using molybdenum disulfide (MoS2) as a photothermal conversion material. Through the foaming process, MPS achieves self-floating and good water transportation performance, which enhances the thermal localization effect on the hydrogel surface and improves energy utilization efficiency (92.95 %), enabling efficient evaporation (3.22 kg m−2h−1). Meanwhile, due to the coupling of P(SA), MPS exhibits excellent salt resistance, maintaining a long-term evaporation rate of 2.8 kg m−2h−1 in high concentration saltwater (20 wt%). The porous structure and interconnected polymer chains enhance the mechanical performance of MPS, making it highly compressible and convenient for collecting freshwater marine and wilderness environments. The preparation strategy of MPS provides a feasible method to simultaneously improve the performance and durability of the interface steam generator in practical applications.